Portland cement



Patented Dec. 17, 1940 UNITED STATES i I'm-hall PATENT OFFICE PORTLANDCEMENT California No Drawing.

Application January 14, 1939,

Serial N0. 251,046

11 Claims.

This invention relates generally to improvements in Portland cements andhas for its primary object to provide Portland cements having certainindividual or combined properties, principally with respect toplasticity, workability and low specific gravity, that render themsuperior to the ordinary Portland cements for a variety of particularuses. The present application is a continuation in part of our copendingapplication Serial Number 199,685 filed April 2, 1938, for Portlandcements.

One of our main purposes is to provide a Portland cement capable offorming cementitious mixtures, whether as neat cements, aggregatecontaining cements, or concrete, of abnormally F ties, i. e., abnormallyin the sense that c gravities are substantially below the specificgravitles of other cementitious mixtures of corresponding aggregatecontent (if aggregate is used) and water-cement ratio. Generallyspeaking, this object is accomplished by artificially incorporatin inthe ment an amount of a r su n ially in excess 0 equan i y 9 --air atnormally would be contained in the dry cement, or put into a wetcementitious mixture as a possible incident of the usual operations formixing water and cement. Accordingly, it is in this sense that we statethat air is artificially held in the cement, i. e., by a medium otherthan the cement alone and by itself.

While in the broad aspects of the invention an amount oi. air requiredto give the mixed cement its desired low specific gravity may beincorporated in the cement artificially by any suitable medium, weprefer to employ a medium whereby small particles of air are held indirect association with or are mechanically entrapped with theindividual cement particles. In accordance with the invention we admixor intergrind with the cement a filming material which adheres to thecement particles, and retains minute air films directly against thecement particles, or against the filming material. In this manner itbecomes possible to retain in the cement an amount of air such that whenthe cement is for example made into a water slurry, the specific gravityof the slurry will be considerably below the specific gravity of aslurry composed of ordinary Portland cement and a correspondingpercentage of water. As a preferred medium for entrapping air in thecement as described, we intimately admix or intergrind any suitablePortland cementwith the proper Percentage of w commercially known un ere ra e name Vinsol. This gasoline-insoluble resin which we use, andrefer to hereinafter simply as the resin," may be produced by extractingresinous 5 pine wood with a coal tar hydrocarbon, removing thehydrocarbon by evaporation, leaving a residue comprising a mixture ofwood rosin and the gasoline-insoluble resin. This resin then isseparated i'rom the wood rosin by extracting the 10 latter by a suitablepetroleum hydrocarbon in WhlCh the wood rosin is soluble.

As another feature of the invention having major importance, the resinhas been found to improve the plastic properties of Portland ce- 15ments in generaL'and as to this aspect as well as the first startedobject of the invention, the advantages are not to be regarded aslimited to Portland cements of any particular type or composition. Forexample, the plastic properties of a normal Portland cement manufacturedby intergrinding the resin with Portland cement clinker containing theusual amount of gypsum, are markedly improved by the presence of theresin. Also, the resin has been found correspondingly effective forimproving the properties of plastic Portland cements containing othermaterials adapted to increase the plasticity and workability of thefinished cement. Although of secondary importance, another advantage inthe 30 use of the resin is its effectiveness as a grinding aid, 1. e.,an admixture that reduces the energy required to grind the clinker to agiven fineness level. Like other grinding aids, the resin apparentlyacts as a dispersing agent, tending to 35 free or disperse into theclinker being ground, fine particles that otherwise tend to build up inlayers on the grinding media and wall of the mill and thereby preventdirect interaction between the grinding surfaces. 40

Referring particularly to plastic cements, the resin may be intergroundwith Portland cement clinker containing other material adapted to givegreater plasticity to the finished cement. We may use one, or a mixture,of two general types of such materials, the effect of which is topromote formation of particle size distribution and increased specificsurface which enhance the plastic properties of the finished cement. Onetype of such materials may be classed as chemically inert substances,for example natural sand, and particularly sands relatively richnT'fiEE' quartz such as result from weathering of granite rocks. Thesecond type are active materials in the sense that they are reactivewith lime released in the cement during hydration. Pouzzolanicmaterials, for example certain shm marine igi ccurring as marine sed'imof Miocene Age in the Upper Puente of Southern California, areillustrative. These shales are characterized by their pronouncedpouzzolanic activity. The Pouzzolan, like sand, has the effect of aidingin developing a product of particle size distribution and specificsurface especially desirable for plastic cement, and it has theadditional property, by reason of its capacity for reaction with limereleased from the cement during hydration, of increasing the strengthobtained in mortars at late ages.

The improved properties of a normal Portland cement interground with theresin in different proportions, are illustrated in Table I below. Thecontrol sample A consisted of 1816 grams of Portland cement clinkermixed with 69 grams of gypsum and subjected to two-stage grinding in aball mill, the first stage consisting of 900 revolutions of the millcharged with 45 lbs. of 1%" balls, and the second stage 1820 revolutionsof the mill recharged with '70 lbs. of to /2 balls. Samples B, C and Dwere cements prepared from the same stock as the control sample anddiffering in composition only in being inter- 30 ground with smallamounts of the resin in the proportions indicated in the table. Allsamples ingly improved properties of cements B, C and D, however, aretheir superior plasticity and workability. Each of these cements whenmixed with water in the percentages indicated for neat cement, displaysexceptional plasticity and smoothness in working. When mixed with waterin sand mortars such as are used in plaster or stucco construction,these cements exhibit unusual workability and highly desirable plasticproperties.

For purposes of comparison, the table shows corresponding properties ofan ordinary commercial plastic Portland cement, which is generallyregarded as having good workability and plastic properties. Cements B, Cand D are found to be superior to cement E in plastic properties, asdemonstrated by workability tests, and to have these superior propertiesnotwithstanding the fact that their finenesses are considerably belowthe fineness of cement E. This fact is of course significant in that thecements contemplated by the invention may be manufactured atconsiderable savings in grinding costs, and still surpass in plasticproperties, the more finely ground plastic cements of ordinarycompositions. Note also that in the tabulated comparison of the plastermortar tensile strengths of samples B and E, the former showssubstantially the same strengths as the commercial plastic cement at oneday and three days, and a tendency to excel in strength at seven days.

Table I Per- Std. 1-3 Tensile Setting time strength Fmeness Gmdmg 31;Perinitial m1 zfgf f plaster sand Sern- Perpancent g mortar 0 p18Composition cent sion wager 0/0720 1 J Hr M" H M D 7n 1) mig z in r. in.l 28 1D 3D 7D crons balls balls were subjected to grinding under exactlythe same conditions so that their differences in fineness are due solelyto the presence of the resin. Samples B, C, and D are shown to havesubstantially larger proportions of particle sizes within the 0 to 20micron range, and greater specific surfaces than the control sample. Netexpansions in the standard autoclave test are but slightly higher forthe samples interground with the resin, and for all practical purposesare as satisfactory as the control sample in this respect. Setting timesand tensile strengths are satisfactory, although it is indicated thatwhere, as in sample D, the resin content is increased to as 65 high as0.50%, the final setting time may be delayed and the initial tensilestrength materially reduced. It is to be noted, however, that with suchproportions of the resin present, the strength developed at periods suchas seven days or longer is as high as the strength developed in cementsof lower resin content. Although the setting times are somewhat longerfor cements B, C and D, this is desirable for most work in whifi plasticcements are used. The outstand- Table II shows a comparison ofproperties between the same control sample given in Table I, and cementsF to J prepared by intergrinding samples of the control stock with theresin and sand (samples F and G) and resin with pouzzolanic shale(samples H, I and J), in the percentages indicated. All samples weresubjected to the same grinding time and procedure as has been set forthfor the cements of Table I.

It will be noted that with the normal amount of grinding given cementsin the series shown in Table II, cements F, G, H, I and J showrelatively high finenesses as compared with the control sample. Thesecements have the advantage of requiring relatively small amounts ofgrinding energy to produce reasonably high finenesses. Table II alsopresents data for autoclave expansion. These data show that the resinand sand, and resin and pouzzolanic cements, exhibit materially lessautoclave expansion than the control cement. It will be seen that thisvalue may be in the order of one-half of the value obtained by thecontrol cement. workability tests have demonstrated that cements F, G,H, I and J are UUWH'UOI l IUHO, e-Aua-l COATING OR PLASTIC. l

8 8 2,225,150 3 Q markedly superior to the control and previously theusual low density or specially made aggre- 1 known cements with regardto the plastic propergates. In the discussion to follow, we refer towith water in the percentages indicated for neat cements of the typecontemplated generally by ties produced in neat pastes and in sandmortars the invention, but in which the resin content is 5 such as areused for plaster and stucco work. suiflciently high (and perhaps higherthan may 5 Table II Fineness Grinding time lo Pegeentnet ex ansionSample COIHPOSIUOD Percent W040 Specific 45 gfiil ib 111C112:

microns surface l A {clinker &3: 54.3 1953 Rev.900.. Rev. 1320 +0.490

' 87 F 61.4 2005 do do.- +0.276

911 87 G gff 53.3 2059 do do.-..- +0.2ss 2o 87 H g f 59.3 2216 .do do+0.24o 3 9.7 l .3. 1 s1 I H 61.3 2238 .do do +0.274 25 9:65 s7 1 S1363.4 2236 do 40.260

Pouzzolan 9. 55

While the tables-shomceitaimpercentages gi be required merely to enhancethe plasticity and sand and pouzzolan to be used, ti ese workability oithe cement), say around 0.50% by m be added in any suitable percentagesprp; weight of the dry cement, to substantially reductive esul't'srordiifarily the necessary duce the specific gravity of wet mixtures ofthe amountoff'silifin either type oi. plastic cecement. ment need notexceed 0.50% by weight of the Included among additional distinguishingclinker mixture, and usually smaller percentcharacteristics andproperties oi the present ceages within the range of from 0.05% to 0.25%ment, is the capacity of a slurry made of the 3 will suflice. Theproportions of sand or pouzcement for being pumped easily and carried 1zolan normally will be under substantially 30% through the pumpingsystem, piping, conduits, 40 "1 by weight of the entire clinker mixture.The etc., with a minimum of applied pressure. The tabulated flnenessesalso are typical only, since cement yields a slurry of unsual mobilityas comthe resin desirably afiects the properties of the pared withslurries made from cements which cement in the respects noted where thecement have been used up to the present; that is to say,

is ground to fineness levels below or in excess of a slurry made fromthe present cement has the 45 those given. property of unusually highrate of increase in 1 We have previously referred to the capacity rateof flow with increases in pressure. Anof the resin when intimatelyadmixed with the other desirable property of the cement is its cement,as by intergrinding, to cause the finished capability of maintainingposition after bein cement to have thin films of air adsorbed uponplaced in any particular location. This propits surface and to causethese films to be re erty is associated with yield point or theprestained when the cement is mixed with water to sure required to causethe inception of flow in -4 form a slurry or other cementitious mixture.It the slurry. Cements used heretofore exhibit is to be understood thatthis adsorbed air is not yield points which are far below the desiredlevel i present as large bubbles or in a form such as when made intoslurries of pumpable consistency. 55 I to cause the slurry to exhibitfoaming or froth- Slurries made of the present cement have sub-- 1 ingtendencies, but is present as extremely mistantially higher yield pointsthan have been ob- I nute films distributed throughout the slurry tainedwith the common Portland cements. The 5 mass on the cement particles.There may be, pumpability of such slurries is not impaired but however,in addition to the air films adhering is actually much greater becauseof the greater 60 directly to the cement particles, more airincormobility of the slurry. porated in the slurry in the form of smallair Slurries made of a mixture containing the particles or bubblesbetween the cement partipresent cement have the further desirablepropcles and held or stabilized within the slurry by erty of maintainingfluidity for a period of time reason of the attraction for air, or airstabilizsuflicient to allow placement of the body of the 65 ing effect,exhibited by the resin. As mentioned, slurry in desired locations remotefrom the I one of the distinguishing characteristics, aside place ofmixing. Under such circumstances, the 1 from increased plasticity andworkability, of the setting and hardening reactions of the cementpresent type of cement is its abnormally low must be so controlled thatthey are retarded to specific gravity. Advantage may be taken of thisthe extent that the fluidity of the slurry will not 70 property forvarious purposes where low density seriously be impaired by increasingrigidity recements are desirable, and also for light weight sulting fromthe setting action of the cement. concretes, for which purpose it may bedesir- Cements of the present invention yield slurries able to utilizetogether with the present type of which retain their fluidity and arepumpable for (Q cement, suitable light weight aggregate such asconsiderable periods of time even at relatively high temperatures. Inthis respect they compare favorably with the most satisfactory cementswhich are now in use.

The present cements are further characterized in a respect thatdistinguishes them from many cements heretofore known to the art, inthat they may be ground to high finenesses and still display thedescribed properties. In the past it has been common to grind cementscoarsely to enhance some of the properties discussed above. However,this has not been a satisfactory means for obtaining such propertiessince coarsely ground cements tend to settle in slurry suspensions andsegregation occurs. It is also diflicult to produce workable slurriesfrom such cements because coarsely ground cements tend to give harshwater-cement mixtures at all water-cement ratios. The invention permitsthe use of cements which are unusually finely divided and possessed ofmany desirable properties attributable to fine grinding, and at the sametime enables the cement to display those properties which it has beenattempted in the past to obtain by coarser grinding, but without theaccompanying or resulting disadvantages men-- tioned.

As will be understood, the resin is incorporated in the cement in anamount determinable in accordance with the properties desired in thecement slurry or other cementitious mixture to be produced. This amountwill usually be about 0.5%, or somewhat more, by weight of the finishedcement, but may be varied within limits as required by the properties tobe developed in the cement. In general, 0.5% by weight of the resin willproduce satisfactory specific gravities and fluidity when the cement ismixed with water to form a slurry. Smaller amounts of resin will resultin increased specific gravity and somewhat lower mobility of the slurrypaste. The fineness to which the cement is ground may be that which iscommon for regular Portland cements or preferably somewhat higher. Forexample this fineness may be defined as a specifio surface of 1500 to1800 square centimeters per gram and preferably as high as 2200 squarecentimeters per gram, as determined by the instrument known as theWagner turbidimeter which is described in Proceedings of the AmericanSociety for Testing Materials, vol. 33, part II, page 553, 1933.

Although it is preferred to intergrind the resin by introducing it intothe unground clinker and gypsum as hereinabove described, other methodsof distribution of the resin throughout the cement may also be employed.For example, if a two stage grinding process is used the clinker andgypsum may be ground without the resin in the first stage and the resinmay be introduced following this grinding operation so that theresin-cement mixture is subjected to intergrinding in the secondgrinding stage. The resin may also be finely divided and merely mixedwith finished cement in a suitable mixing apparatus or it may bedistributed throughout the cement by such a process as that described inthe copending application of Ira C. Bechtold, Serial Number 185,309filed January 17, 1938.

The table below shows specific gravity data relating to slurries madewith a cement produced in accordance with this invention as comparedwith specific gravity data obtained with a cement of ordinary type. Theslurries were all prepared, as nearly as possible, by identical pro-Table III Weight per cubic foot in pounds Water cement ratio by weightIt is evident that cement A yields a slurry having a markedly lowerspecific gravity than does the ordinary cement, and other tests made,but not tabulated in detail, indicate its distinguishing andcharacteristic properties in the various other respects discussed in theforegoing. The specific gravity of the cement may be varied withinsubstantial limits by varying its air content through regulation of thepercentage of resin admixed or interground therewith, and fineness ofgrinding. For many purposes where an especially light weightcementitious mixture is desired, we may incorporate such a relativelyhigh proportion of air in the cement, that such mixtures will havespecific gravities far below the specific gravities of correspondingcementitious mixtures of other Portland cements. By intergrinding withthe cement around 0.50% of the resin, it is possible to form a slurry(to cite a specific example and basis for comparison) having awater-cement ratio of 0.50 and a weight per cubic foot not substantiallyin excess of pounds. Since weight per cubic foot is a common basis ofdesignating weight or density of cement slurries, a light weight slurryas discussed above may be defined as one Whose specific gravitycorresponds to a per cubic foot weight below substantially the weight(90 pounds) stated.

We claim:

1. A Portland cement having air particles mechanically entrapped withthe cement, said cement including in a mixture therewith a paraffinhydrocarbon-insoluble resin produced by the extraction of comminutedpinewood by a coal tar hydrocarbon, the removal of the volatilesubstances from the extract to obtain a mixture of solid resins, theextraction of such mixture of solid resins by a volatile parafiinhydrocarbon to remove petroleum hydrocarbon-soluble resins from saidresin mixture, and the recovery of said parafiin hydrocarbon-insolubleresin substantially free from said soluble resins, said paraffinhydrocarbon-insoluble resin being provided to aid in the entrapment ofthe air particles and the stabilization of said particles.

2. As a product, Portland cement containing a small percentage of aparafiin hydrocarboninsoluble resin produced by the extraction ofcomminuted pinewood by a coal tar hydrocarbon, the removal of thevolatile substances from the extract to obtain a mixture of solidresins, the extraction of such mixture of solid resins by a volatileparafiin hydrocarbon to remove petroleum hydrocarbon-soluble resins fromsaid resin mixture, and the recovery of said parafiin 10d COMPOSHWONS,

COATING OR PLASTIC.

hydrocarbon-insoluble resin substantially free from said soluble resins,said paraflln hydrocarbon-insoluble resin being uniformly distributedthroughout the cement.

3. As a product, Portland cement containing a parafiinhydrocarbon-insoluble resin, in the proportion of substantially 0.05% to0.50% by weight of the cement, said paraffln hydrocarboninsoluble resinhaving been produced by the extraction of comminuted pinewood by a coaltar hydrocarbon, the removal of the volatile substances from the extractto obtain a mixture of solid resins, the extraction of such mixture ofsolid resins by a volatile paraflln hydrocarbon to remove petroleumhydrocarbon-soluble resins from said resin mixture, and the recovery ofsaid paraflin hydrocarbon-insoluble resin substantially free from saidsoluble resins.

4. As a product, Portland cement containing a small percentage of aparaffln hydrocarboninsoluble resin produced by the extraction ofcomminuted pinewood by a coal tar hydrocarbon, the removal of thevolatile substances from the extract to obtain a mixture of solidresins, the extraction of such mixture of solid resins by a volatileparaflin hydrocarbon to remove petroleum hydrocarbon-soluble resins fromsaid resin mixture, and the recovery of said paramnhydrocarbon-insoluble resin substantially free from said soluble resins,said paraflin hydrocarbon-insoluble resin being uniformly distributedthroughout the cement and coating the individual particles thereof.

5. As a product, Portland cement having air particles mechanicallyentrapped with the cement, said cement including in a mixture therewitha paraiiin hydrocarbon-insoluble resin produced by the extraction ofcomminuted pinewood by a coal tar hydrocarbon, the removal of thevolatile substances from the extract to obtain a mixture of solidresins, the extraction of such mixture of solid resins by a volatileparaffin hydrocarbon to remove petroleum hydrocarbon-soluble resins fromsaid resin mixture, and the recovery of said parafiin hydrocarboninsoluble resin substantially free from said soluble resins, saidparafiin hydrocarbon-insoluble resin being mixed with said cement in theproportion of substantially 0.05% to 0.50% by weight of the cement, andsaid paraffin hydrocarboninsoluble resin being uniformly distributedthroughout the cement and coating the individual particles thereof tostabilize said particles throughout the cement.

6. As a product, a iund mixture of Portland cement and asilica-containing material adapted to increase the plasticity of thecement. and a paraffin hydrocarbon-insoluble resin produced by theextraction of comminuted pinewood by a coal tar hydrocarbon, the removalof the volatile substances from the extract to obtain a mixture of solidresins, the extraction of such mixture of solid resins by a volatileparaffin hydrocarbon to remove petroleum hydrocarbon-soluble resins fromsaid resin mixture, and the recoveryFi said paraflinhydrocarbon-insoluble resin substantially free from said soluble resins,said paraflin hydrocarbon resin being uniformly distributed throughoutsaid mixture and coating the individual particles of said cement andsilica-containing material therein.

7. As a product, a ground mixture of Portland cement and asilica-containing liine reactive material adapted tourism-ace theplasticity of the cement, and a parafiin hydrocarbon-insoluble resinproduced by the extraction of comminuted pinewood by a coal tarhydrocarbon, the removal of the volatile substances from the extract toobtain a mixture of solid resins, the extraction of such mixture ofsolid resins by a volatile paraffin hydrocarbon to remove petroleumhydrocarbon-soluble resins from said resin mixture, and the recovery ofsaid parafl'in hydrocarbon-insoluble resin substantially free from saidsoluble resins, said paraifin hydrocarboninsoluble resin being uniformlydistributed throughout said mixture and coating the individual particlesof said cement and silica-containing material therein.

8. As a product, a groundmixture of Portland cement and sand amparaffinhydrocarboninsoluble resin produced by the extraction of comminutedpinewood by a coal tar hydrocarbon, the removal of the volatilesubstances from the extract to obtain a mixture of solid resins, theextraction of such mixture of solid resins by a volatile paraflinhydrocarbon to remove petroleum hydrocarbon-soluble resins from saidresin mixture, and the recovery of said parafin hydrocarbon-insolubleresin substantially free from said soluble resins, said parafiinhydrocarbon-insoluble resin being uniformly distributed throughout saidmixture and coating the individual particles of said cement and sandtherein.

9. As a product, a ground mixture containing Portland cement and lessthan 30% by weight of sand, and from substantially 0.05% to 0.50% byweight of a paraffin hydrocarbon-insoluble resin produced by theextraction of comminuted pienwood by a coal tar hydrocarbon, the removalof the volatile substances from the extract to obtain a mixture of solidresins, the extraction of such mixture of solid resins by a volatileparafiin hydrocarbon to remove petroleum hydrocarbon-soluble resins fromsaid resin mixture, and the recovery of said paraffinhydrocarbon-insoluble resin substantially free from said soluble resins,said paraffin hydrocarboninsoluble resin being uniformly distributedthroughout said mixture and coating the individual particles of saidcement and sand therein.

10. As a product, a ground mixture containing Portland cement and lessthan 30% by weight of pouzzolanic shale and from substantially 0.05% to0.50% by weight of a paraffin hydrocarbon-insoluble resin produced bythe extraction of comminuted pinewood by a coal tar hydrocarbon, theremoval of the volatile substances from the extract to obtain a mixtureof solid resins, the extraction of such mixture of solid resins by avolatile paraflin hydrocarbon to remove petroleum hydrocarbon-solubleresins from said resin mixture, and the recovery of said paraflinhydrocarbon-insoluble resin substantially free from said soluble resins,said parafiin hydrocarbon-insoluble resin being uniformly distributedthroughout said mixture and coating the individual particles of saidcement and shale therein.

11. Portland cement having air particles mechanically entrapped with theindividual particles of cement, said cement including a mixturetherewith of a paraflin hydrocarbon-insoluble resin produced by theextraction of comminuted pinewood by a coal tar hydrocarbon, the removalof the volatile substances from the extract to obtain a mixture of solidresins, the extraction of such mixture of solid resins by a volatileparafiin hydrocarbon to remove petroleum hydrocarbon-soluble resins fromsaid resin mixture, and the recovery of said parafiinhydrocarbon-insoluble resin substantially free from said soluble resins,said cement and paraffin hydrocarbon-insoluble resin mixture whenadmixed

